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2ba45a60 DM |
1 | /* |
2 | * Copyright (c) 2012 Clément Bœsch | |
3 | * | |
4 | * This file is part of FFmpeg. | |
5 | * | |
6 | * FFmpeg is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU Lesser General Public | |
8 | * License as published by the Free Software Foundation; either | |
9 | * version 2.1 of the License, or (at your option) any later version. | |
10 | * | |
11 | * FFmpeg is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | * Lesser General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU Lesser General Public | |
17 | * License along with FFmpeg; if not, write to the Free Software | |
18 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
19 | */ | |
20 | ||
21 | /** | |
22 | * @file | |
23 | * WebVTT subtitle decoder | |
24 | * @see http://dev.w3.org/html5/webvtt/ | |
25 | * @todo need to support extended markups and cue settings | |
26 | */ | |
27 | ||
28 | #include "avcodec.h" | |
29 | #include "ass.h" | |
30 | #include "libavutil/bprint.h" | |
31 | ||
32 | static const struct { | |
33 | const char *from; | |
34 | const char *to; | |
35 | } webvtt_tag_replace[] = { | |
36 | {"<i>", "{\\i1}"}, {"</i>", "{\\i0}"}, | |
37 | {"<b>", "{\\b1}"}, {"</b>", "{\\b0}"}, | |
38 | {"<u>", "{\\u1}"}, {"</u>", "{\\u0}"}, | |
39 | {"{", "\\{"}, {"}", "\\}"}, // escape to avoid ASS markup conflicts | |
40 | }; | |
41 | ||
42 | static int webvtt_event_to_ass(AVBPrint *buf, const char *p) | |
43 | { | |
44 | int i, skip = 0; | |
45 | ||
46 | while (*p) { | |
47 | ||
48 | for (i = 0; i < FF_ARRAY_ELEMS(webvtt_tag_replace); i++) { | |
49 | const char *from = webvtt_tag_replace[i].from; | |
50 | const size_t len = strlen(from); | |
51 | if (!strncmp(p, from, len)) { | |
52 | av_bprintf(buf, "%s", webvtt_tag_replace[i].to); | |
53 | p += len; | |
54 | break; | |
55 | } | |
56 | } | |
57 | if (!*p) | |
58 | break; | |
59 | ||
60 | if (*p == '<') | |
61 | skip = 1; | |
62 | else if (*p == '>') | |
63 | skip = 0; | |
64 | else if (p[0] == '\n' && p[1]) | |
65 | av_bprintf(buf, "\\N"); | |
66 | else if (!skip && *p != '\r') | |
67 | av_bprint_chars(buf, *p, 1); | |
68 | p++; | |
69 | } | |
2ba45a60 DM |
70 | return 0; |
71 | } | |
72 | ||
73 | static int webvtt_decode_frame(AVCodecContext *avctx, | |
74 | void *data, int *got_sub_ptr, AVPacket *avpkt) | |
75 | { | |
f6fa7814 | 76 | int ret = 0; |
2ba45a60 DM |
77 | AVSubtitle *sub = data; |
78 | const char *ptr = avpkt->data; | |
79 | AVBPrint buf; | |
80 | ||
81 | av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED); | |
82 | if (ptr && avpkt->size > 0 && !webvtt_event_to_ass(&buf, ptr)) { | |
83 | int ts_start = av_rescale_q(avpkt->pts, avctx->time_base, (AVRational){1,100}); | |
84 | int ts_duration = avpkt->duration != -1 ? | |
85 | av_rescale_q(avpkt->duration, avctx->time_base, (AVRational){1,100}) : -1; | |
f6fa7814 | 86 | ret = ff_ass_add_rect_bprint(sub, &buf, ts_start, ts_duration); |
2ba45a60 | 87 | } |
2ba45a60 | 88 | av_bprint_finalize(&buf, NULL); |
f6fa7814 DM |
89 | if (ret < 0) |
90 | return ret; | |
91 | *got_sub_ptr = sub->num_rects > 0; | |
2ba45a60 DM |
92 | return avpkt->size; |
93 | } | |
94 | ||
95 | AVCodec ff_webvtt_decoder = { | |
96 | .name = "webvtt", | |
97 | .long_name = NULL_IF_CONFIG_SMALL("WebVTT subtitle"), | |
98 | .type = AVMEDIA_TYPE_SUBTITLE, | |
99 | .id = AV_CODEC_ID_WEBVTT, | |
100 | .decode = webvtt_decode_frame, | |
101 | .init = ff_ass_subtitle_header_default, | |
102 | }; |